Technical data

Glossary
Software
System Manual, 07/2009, C79000-G8976-C222-07
451
The GPS receiver receives data from a maximum of six satellites and calculates its position
based on these values. Once the position has been calculated, the transmission time of the
data from the individual satellites can be calculated. The GPS world time (UTC) is calculated
in the system based on these values.
Graphics Designer
The Graphics Designer is a vector-oriented drawing program for creating process pictures.
Complex process pictures can be created using a wide variety of graphic objects from an
object and style palette.
ST7cc Config uses the ODK interface of the Graphics Designer to create picture typicals for
the SINAUT subscribers and to make these available to the WinCC configuration engineer in
a sample picture for use in further process pictures.
GSM
(Global System for Mobile communications)
Worldwide standard for wireless transmission of voice, data, fax and text messages (SMS).
GSM-based wireless networks can be found in many countries throughout the world. A
distinction is made according to frequencies: PCS 850 MHz, GSM 900 MHz, DCS 1800 MHz
and PCS 1900 MHz.
Image memory / send buffer
A TIM has a send buffer and an image memory for buffering send messages.
Before it is forwarded to the communications partner, each message is entered in the send
buffer. Once it has been sent, the message is cleared from the send buffer. A message is
transmitted according to either the → send buffer principle or the → image memory principle.
The user specifies the transmission principle during configuration of the data messages.
The storage capacity of the send buffer depends on the particular TIM type and ranges from
10 000 to 56 000 data messages.
Image memory principle
A fixed position is reserved in the image memory for each data message transferred to the
TIM for transmission. Each newly transferred message always overwrites the old message in
the image memory. The image memory therefore contains all data messages with their most
recent content from the process.
If a send message is entered using the image memory principle, only a reference to the
location of the message in the message image memory is entered. If the TIM has not yet
been able to transmit the message when the same message is transferred to it again, the
message is not entered in the send buffer a second time, but rather the image is simply
updated.
At the time of transmission, the message is sent with its latest content from the image
memory. Only then can the message be entered in the send buffer again.
Transmission using the image memory principle achieves the following: